1. Field of the Invention
The invention is directed to a method and apparatus for releasing spring applied hydraulically released brakes when the source of pressurized hydraulic fluid fails.
2. Description of the Prior Art
Large work vehicles are increasingly using spring applied hydraulically released brakes. These brakes are always applied unless released by hydraulic pressure. Typically these brakes cannot be released unless the engine is running and the source of pressurized hydraulic fluid, a pump, is directing hydraulic fluid to the brakes. Sometimes the engines or the hydraulic pumps on these machines break down in remote locations where it is inconvenient to repair. This is especially true in forest fire applications where moving the vehicle is time critical. The repair person may need to tow the vehicle to a more suitable location to perform repairs. However as the brakes are in an applied mode it makes towing the vehicle difficult if not impossible. Therefore an external source of hydraulic pressure needs to be applied to the brakes to release the brakes before towing the vehicle.
Pressurized carbon dioxide cartridges are used in a number of applications. Simple hand held applicators are used to apply pressurized carbon dioxide gas to inflating tires, inflating air bladders on athletic shoes and skates and other applications. These hand held applicators may have variable flow valves to control the application of carbon dioxide gas.